Suzuki XL7 2007 Service Manual page 1568

5A-158 Automatic Transmission:
Noise
NOTE
Do not confuse this noise with pump whine
noise, which is usually noticeable in PARK,
NEUTRAL and all other gear ranges. Pump
whine will vary with line pressure.
You may notice a torque converter whine when the
vehicle is stopped and the transmission is in DRIVE or
REVERSE. This noise will increase as you increase the
engine RPM. The noise will stop when the vehicle is
moving or when you apply the torque converter clutch,
because both halves of the converter are turning at the
same speed.
Perform a stall test to make sure the noise is actually
coming from the converter:
1. Place your foot on the brake.
2. Put the gear selector in DRIVE.
CAUTION
!
You may damage the transmission if you
depress the accelerator for more than 6
seconds.
3. Depress the accelerator to approximately 1,200
RPM for no more than 6 seconds.
A torque converter noise will increase under this load.
Torque Converter Clutch Shudder
The key to diagnosing torque converter clutch (TCC)
shudder is to note when it happens and under what
conditions.
TCC shudder which is caused by the transmission
should only occur during the apply or the release of the
converter clutch. Shudder should never occur after the
TCC plate is fully applied.
If Shudder Occurs During TCC Apply or Release
If the shudder occurs while the TCC is applying, the
problem can be within the transmission or the torque
converter. Something is causing one of the following
conditions to occur:
• Something is not allowing the clutch to become fully
engaged.
• Something is not allowing the clutch to release.
• The clutch is releasing and applying at the same time.
One of the following conditions may be causing the
problem to occur:
• A restricted release orifice
• Defective friction material on the TCC plate
If Shudder Occurs After TCC has Applied
If shudder occurs after the TCC has applied, most of the
time there is nothing wrong with the transmission.
The TCC is not likely to slip after the TCC has been
applied. Engine problems may go unnoticed under light
throttle and load, but they become noticeable after the
TCC apply when going up a hill or accelerating. This is
due to the mechanical coupling between the engine and
the transmission.
Once the TCC is applied, there is no torque converter
fluid coupling assistance. Engine or driveline vibrations
could be unnoticeable before TCC engagement.
Inspect the following components in order to avoid
misdiagnosis of TCC shudder. An inspection will also
avoid the unnecessary disassembly of a transmission or
the unnecessary replacement of a torque converter.
• Spark plugs
Inspect for improper gap, cracks, high resistance or a
broken insulator.
• Ignition coil
Look for a white discoloration or bulls eye marks on
the coil. This indicates arcing while the engine is
misfiring.
• Fuel injector
There may be an intermittent internal electrical short.
• Engine mounts
Vibration from loose or weak mounts can be multiplied
by TCC engagement.
• Axle joints
Check for proper installation, wear and/or damage.
Replace the torque converter if any of the following
conditions exist:
• External leaks appear in the hub weld area.
• The converter hub is scored or damaged.
• The converter pilot is broken, damaged, or fits poorly
into the crankshaft.
• You discover steel particles after flushing the cooler
and the cooler lines.
• The pump is damaged, or you discover steel particles
in the converter.
• The vehicle has TCC shudder and/or no TCC apply.
Replace the torque converter only after all hydraulic
and electrical diagnoses have been made. The
converter clutch material may be glazed.
• The converter has an imbalance which cannot be
corrected. Refer to "Flexplate/Torque Converter
Vibration Test".
• The ATF is contaminated with engine coolant.
• An internal failure occurs in the stator roller clutch.
• Overheating produced heavy debris from clutch
material.
• You discover steel particles or clutch lining material in
the fluid filter or on the magnet, when no internal parts
in the unit are worn or damaged. This condition
indicates that lining material came from the converter.